network research lab. sejong university, korea jae-kwon seo, kyung-geun lee sejong university, korea

Network Research Lab.Network Research Lab.Sejong University, Korea

Jae-Kwon Seo, Kyung-Geun LeeSejong University, Korea


Introduction

Related works

Proposed scheme

Simulation Experiment

Numerical Analysis

Conclusion

2


Mobility support in IPv6 (MIPv6)

◦ Home Agent (HA)

◦ Temporary address, Care-of-Address (CoA)

◦ A mobile node(MN) moves to a foreign network,

Binding update : MN->HA

3

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HA

MN

CN

1

2

3

5

4

Intercept&

Encapsulation

①, : Binding Update/Acknowledge②③, , : First User Data Packet Delivery④ ⑤


◦ Authenticating binding-update requires 1.5 RTT between MN and CN

◦ One RTT is needed to update the HA

◦ A Mobile Node has to register to the HA every handover occurs

5


Two addresses

◦ Regional CoA (RCoA) : MAP prefix based◦ On-link CoA (LCoA) : current AR prefix based

Mobility Anchor Point (MAP)

◦ Local HA◦ Intercepts the packets destined to RCoA◦ Tunnels the packets to the LCoA

Two binding updates

◦ Regional binding update : RCoA -> HA◦ Local binding update : LCoA -> MAP

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MAP

HACN

Internet

MAP

oldAR

newAR

MAP domain

MN

Local BU

(Home address, RCoA)

(RCoA,

Home BU

Local BU

LCoA’)LCoA )


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Binding update

Binding Ack.

Data transfer

8

reduces wired signaling cost& reduces update latency

MN AR HA or CN

MN AR HA or CNMAP

MIPv6

HMIPv6


Efficiently in supporting micro-mobility◦ Within a MAP domain

Not appropriate in supporting macro-mobility◦ Inter-MAP domain handover◦ longer handover latency with more packet loss

9


HA CN

Higher layer

Lower layer

: MAP

: AccessRouter

INTERNET


Velocity-based MAP selection scheme

◦ Fast MNs select the HMAP◦ Slow MNs select the LMAP

Load control scheme

◦ The MAP checks the maximum number of MNs◦ Decides whether to receive or to reject a registration request of the MN◦ Rejected MN selects the next candidate MAP

Velocity based + load control, velocity based + moving range of the MN…

11


Estimated velocity may not reflect the current velocity

MNs do not always move with constant velocity and direction

Slow MN eventually encounters the inter-domain handover but this case is not considered

This paper proposes a MAP changing scheme using a virtual domain (VD)

12


Simple method

◦ Considering only current moving direction and position of the MN

◦ Reduces significant overhead generated by complex computation procedure

◦ Not responsible for wrong prediction

Virtual domain

◦ Assigning ARs to the domain of the Higher layer MAP (HMAP)

13


Changing Point

1 : MN moves to the changing point of the VD2 : MAP changing request message

3

3 : Binding Update (LCoA)

4

4 : Biding Ack.

5

5 : Binding Update (RCoA)

6

6 : Binding Ack.


Check the Registration Table

MN PAP NAP edge AR L(H)MAP H(L)MAPCN,HA

Deliver Packet

Deliver Packet

Authentication request

Authentication response

Reassociation request

Reassociation response

Layer 2 Handover

RS message (include AP’s L2 address)

RA message (MAP-changing request)

Local Binding-Update

Binding-Ack.

Binding-Update

Local Binding-Ack.

Deliver Packet

Deliver Packet

MAP Changing

PAP : previous access pointNAP : new access point (CP of LMAP domain (or VD))edge AR : edge of LMAP domain (or VD)

if (MN’s current MAP address = L(H)MAP’s address) {send MAP-changing request included in RA message}else {send normal RA message}

only


The changing point is AP (802.11) or BS(802.16)

The MAP changing procedure is similar to the inter-domain handover ◦ Except for the generating procedure of the LCoA

Inter-domain handover occurs◦ MN completes the handover using binding update with LCoA only.

Does not generate packet loss◦ The MAP changing procedure changes the routing path only from CN to MN while

receiving packets

Load concentration of a HMAP is distributed in VD◦ MNs registered with HMAP and LMAP coexist in VD

17


◦ Simulation topology NS-2

18


RTT between MN and CN

19

Furthest selection scheme Nearest selection scheme MAP changing scheme


When the ping-pong movement occurs

20


Average number of the encapsulated packets at HMAP (HMAP load)

21


State diagram for random walk mobility model

22

ring 0

ring K

ring Kring K

ring K

ring 1 ring 1

ring 1

ring 1ring 1

ring 1

ring K

ring K

MAP

HA

Internet

0 KK-1K-221

K K 1,K K

, 1K K 1, 2K K

• MAP domain consist of rings


A ring k is composed of 6k subnets except the ring 0 The number of subnets

If the MN is located in a subnet of ring k The probability that a movement will result in an increase or decrease in the

distance from the center subnet

23

1

( 1)( ) 6 1 6 1 3 ( 1) 1

2

K

k

K KN K k K K

1 1( )3 6

p rk

1 1( )3 6

p rk


Markov chain as the distance between the current location of the MN and center of the domain

The transition probabilities

where q is the probability that a MN stays in the current subnet

The steady state probability

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1 1

3 6

(1 ) if 0, 1 (1 ) if 1

1 1(1 ) if 1, 1 3 6

k

q kk k q k K

q k Kk k k

1,

-1

0 for 10,,

i i

k

ip p k KKk K


Internet

ring n

ring n

ring n

ring n

ring K

ring K

ring K

ring K

ring n

d

ring K

(H L)MAP chnaging

d(L H)MAP chnaging

HMAP

LMAP

LMAPLMAP

CNHA

: area 1

: area 3

: area 2

: MN


0

0.05

0.1

0.15

0.2

0.25

20 40 60 80

Percentage of fast MNs (%)

Bin

ding

upd

ate

cost

FurthestNearestVelocityChanging

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

3 4 5 6ring of the outermost subnets K

Bin

ding

upd

ate

cost



0

0.2

0.4

0.6

0.8

1

1.2

10 20 30 40 50Number of MNs

Pac

ket

pro

cess

ing

co

st


0

10

20

30

40

50

60

10 20 30 40 50Number of MNs

Rel

ativ

e lo

ad a

t HM

AP



HMIPv6 has been proposed to compensate for the problems in employing MIPv6◦ but, longer handover latency than MIPv6 when inter-domain handover occurs◦ load concentration at a particular MAP

This paper proposes MAP changing scheme using VD of HMAP◦ predictably changes the MAP

May not assure accurate prediction◦ Reduces overhead generated by complex computation procedure

Performance evaluation◦ Average number of registration with HA and CN is increased◦ However, MAP changing scheme reduces inter-domain handover latency◦ And load concentration of the HMAP is distributed

Future work◦ How to decide the optimal range of a VD◦ Simulate the proposed scheme in extended topologies

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network research lab. sejong university, korea jae-kwon seo, kyung-geun lee sejong university, korea

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